Adapter



P 5, 1949' L. G. LAWRENCE I 2,481,027

ADAPTER Filed March 19, 1946' tented Sept. 1949 ADAPTER Leslie 6. Lawrence, Newton @enter, Mass assignor to Raytheon Manufacturing Company, Newton, Mass., a corporation oi Delaware Application March 19, 1946, Serial No. 655,471

This invention relates to an adapter fitting for electron discharge tubes, and more particularly to a fitting useful in conjunction with small space discharge tubes, such as those used in hearing aids, pocket radios or other portable devices intended to be carried on the person.

in such tubes of the fiat-bulb type, the lead-in wires are sealed through a flat press in a single line. These tubes are ordinarily tested with a test set as they come oil the manufacturer's production line, and it may be desired to make tests on them at other times, after they have been put into use. Also, certain tubes are placed on the aging rack, to be given a life test. Tubes of the above type do not ordinarily include pins or prongs soldered to the lead-in wires, since no base is attached to the envelopes of such tubes.

An object of this invention is to devise an adapter fitting whereby tubes of the fiat-bulb type may be readily connected to pin-type sockets for test purposes.

Another object is to provide an adapter by means of which tubes of the so-called sulbminiature type may be rapidly and properly connected to a power supply for test purposes.

A further object is to devise such an adapter which is easy to assemble, easy to disassemble for repair purposes, and is relatively inexpensive.

The foregoing and other objects of the invention will be best understood from the following description of some exemplifications thereof, reference being had to the accompanying drawing, wherein:

Fig. l is a front elevation, partially broken away, of the complete adapter unit, shown with a tube inserted therein.

Fig. 2 is a vertical section through the adapter unit, taken on line 2-4 of Fig. 3;

Fig. 3 is a top plan view of the adapter, partially broken away to show certain details; and

Fig. 4 is a perspective view of a modified spring contact.

Referring to the drawing, the adapter unit as a whole, indicated at I, is shown in Fig. 1 with an electrondischarge tube 2 inserted in one end thereof as the unit would appear when it is being used for the purpose of testing said tube. The tube 2 is preferably of the sub-miniature type, having an electrode structure 3 sealed inside a fiat bulb t, the lead-in conductors 5 for said structure being sealed through a flat press 6 in a single substantially straight line as shown.

The adapter unit i consists of a lower or base portion l and an upper or upstanding portion 8.

3 Claims. (@E. 173-344) 2 a molded disk-shaped base 9 of insulating material having apertures therein in which are rigidly mounted a, plurality of metallic electrically-conducting hollow pins or prongs ill extending downwardly from said base 9. Projecting downwardly from the center of base 9 is a plug 4 I of insulating material having a locating lug thereon which serves to insure that the adapter unit is properly plugged into its receptacle on the test board or rack. Firmly attached to base 9 is a. relatively thin metallic shell it having an inwardly-extending lip or flange It at its upper edge. This shell is attached firmly to base 9 by any suitable means, such as by crimping portions of the lower edge of the shell around or over said. base. Th abovedescribed elements of base portion 71 may be the same as the corresponding parts of a. standard type octal-base glass bulb radio-receiving tube, for example the GSK'IGT/G.

The upper portion 8 of the adapter is made of insulating material, is made in one piece, and includes a lower clamping portion it, of circular cross-section, and an upper prismoidal portion l5 extending upwardly from the center of clamping portion it. This prismoidal portion is of smaller cross-sectional area than portion it, as shown in Fig. 3, and has a cross-section of substantially rectangular form but with arcuate ends. A plurality of elongated parallel interior recesses l6 are formed in portion 8 of the adapter. These recesses are substantially rectangular in'crosssection and extend in a. vertical direction, from the lower edge of clamping portion l4, entirely through portion l4 and into prismoidal portion IE to a, distance such that the length of said recesses is approximately three-fourths of the total length of portion 8. These recesses, for ease in molding and for greater mechanical strength, have the cross-sectional shape shown in Fig. 3 for substantially their entire lengths, but at points close to the ends of said recesses the offset portions taper oil, so that at their upper ends. these recesses are of rectangular configuration. These recesses, as shown, are separated from each other, throughout their lengths, by thin portions ll of the material of the body, so that they are entirely separate from each other and are electrically insulated from each other. Although flve recesses are shown in portion 8, there may be any desired number, for example, four or seven., As will be seen, the recesses are arranged in a straight line.

Small apertures it are drilled through the top surface of prismoidal portion l5 into communi- Base portion I, viewed from the exterior, includes cation with recesses IS, the center of each of said apertures coinciding with the center of its corresponding recess and the apertures all extending parallel to the long dimension of the recesses. Each of these apertures is countersunk, as shown at l9, to a depth such that the countersunk portions of each aperture very nearly meet those of the adjacent apertures.

A plurality of spring contacts 20 are provided, equal in number to the number or recesses. One of these contacts is mounted in each of the recesses l8, and the contacts are of such size and shape with respect to the size and shape of the recesses and they firmly engage the side walls of their respective recesses. Each of the contacts is formed from a phosphor-bronze alloy strip, and is made by bending a short length of such metal strip into the form of a U, and then curving each of the ends inwardly toward the other and then back outwardly, in a semi-ellipse. The sides of the U are pushed out against the side walls of the recesses by the inherent elasticity of the metal. After these contacts have been mounted in their recesses, the lead-in wires of tube 2, which are in a straight line, may be readily inserted in their respective countersunk openings l9 (which are equal in number to the number of lead-in wires). The countersinking of apertures l8 efiectively and efilciently guides the lead-in wires to their respective apertures l8, and the wires pass through said apertures into their respective recesses it, where electrical contact :with their respective spring contacts is accomplished by the passage of the wire between the semi-elliptical portions of said contacts. Good electrical contact is obtained, due to the inherent springiness of these portions.

In order to firmly attach the upper portion 8 of the adapter to the lower portion 1 thereof, a disk member 2|, made of insulating material. is provided. This member is made of such diameter as to slidably fit inside shell I 2. Two diametrically opposite threaded openings 22 are provided in this disk, these openings being aligned with two diametrically opposite apertures 23 in clamping portion I4. Clamping portion I4 is of such a diameter as to overlap lip l3 on its upper surface, while disk 2| extends beyond its edge on its lower surface. Therefore, by insertion and tightening of screws 24 in the aligned openings in the two members, lip I3 will be clamped therebetween, holding disk 2| and portion 8 together and firmly securing both to base portion I and its base pins.

In order to provide electrical connection between spring contacts 20 and the base pins, wires 25 have one end connected to base pins l0 and their opposite ends connected to spring contacts 20. These wires have one end inserted through the respective hollow base pins I 0 and soldered therein, while their opposite ends are inserted through small apertures in the respective metallic spring contacts 20 and are soldered in place therein. countersunk apertures 26 are provided in disk 2| for the passage of wires 25 therethrough, each of these apertures being aligned with a respective one of the recesses It.

If it is desired to replace any of the spring contacts 20, it is only necessary to remove the two screws '24 and lift oiT the upper portion 8 of the adapter, leaving the contacts 20 exposed so that the proper repairs may be made. If more extensive repairs are to be made, the shell l2 may readily be removed from base 9, thereby exposing the entire interior of base portion I.

In use, the adapter I may be plugged into a standard octal-receiving tube socket by inserting the base pins l0 into the corresponding openings in the socket, the corresponding openings being located by means oi plug ii and its locating lug. The leadin wires 5 of a flat press tube 2 may then be readily inserted into the corresponding linearly-disposed openings l8 oi the adapter and pushed therethrough until the wires engage the corresponding spring contacts 20. Proper voltages are then supplied from a suitable power supply to the proper terminals of the Octal-type socket and the desired tests of tube 2 made. If desired, small depressions may be provided in the upper surface of the adapter, adjacent one of the openings I8. When these depressions are filled with paint, they may be used in conjunction with a painted spot adiacent one of the leads 5 of the tube, to enable tube 2 to be rapidly inserted in the adapter with the proper polarity. It will therefore be seen that, with this adapter, tubes of the flat-press type may be easily and conveniently connected to octal-type sockets.

To assemble the device, disk 2| is positioned inside shell l2 by inserting it into the lower or bottom open end thereof. Sprin contacts 20, to which wires 25 have previously been attached, are then brought up to the shell and the free ends of said wires are threaded through apertures 26 in disk 2|. Base 9, with its attached pins I0, is then brought up to the'shell and the wires 25 are threaded through the proper hollow pins l0 and are soldered therein. Shell 2 is then attached to base 9 by crimping, in the usual man ner. Upper portion 8 is then brought up, upstanding contacts 20 are inserted into their corresponding recesses i6, and portion 8 is pushed downwardly until it engages lip l3 of shell i2. Screws 24 are inserted through apertures 23, are threaded into threaded openings 22, and are then tightened to hold portions 1 and 8 securely together.

In Fig. 4 thereds shown a modified type of spring contact 20', a plurality of which may be used in the adapter unit instead of contacts 20 if desired. Contact 20 comprises a strip of phosphor-bronze alloy which is bent into a U- shape, but having its arms bowed slightly inwardly. The two ends of the strip are bent toward each other, as shown, so that they touch each other along a line of contact and then are bent so that they diverge from their line of contact. Lead 5, when inserted into this contact, makes electrical contact therewith along the line of contact of the arms of the U.

Of course, it is to be understood that this invention is not limited to the particular details as described above, as many equivalents will suggest themselves to those skilled in the art. For example, the elements 8 and 2| may be made of any suitable plastic insulating material, such as that known as Lucite, and may be formed in any suitable manner, such as by molding. Various other variations will suggest themselves. It is accordingly desired that the appended claims be given a broad interpretation commensurate with the scope of this invention within the art.

What is claimed is:

1. An adapter for use with a flat-bulb electron discharge tube, including, in combination, a pintype base having a plurality of pins arranged in a circle, an upstanding metallic shell at the periphery of said base, a disk-shaped body of insulating material disposed within said shell, a second body of insulating material disposed exteriorly of said shell, said second body having a plurality of recesses therein arranged in a straight line, a contact element disposed in each of said recesses, means electrically connecting said contact elements separately to the pins of said base, and means for clamping saidtwo bodies together with a portion of said shell therebetween.

2. An adapter for; use with a flat-bulb electron discharge tube, including, in combination, a pintype base having a plurality of pins arranged in a circle, an upstanding metallic shell at the periphery of said base, said shell having an inwardly-extending lip at its upper end, a diskshaped body of insulating material" disposed within said shell, said body engaging the lower surface of said lip, a second body of insulating material disposed exteriorly of said shell, said second body consisting of a circular base portion which engages the upper surface of said lip and an upstanding prismoidal portion, means for clamping said two bodies together on opposite sides of said lip, said second body having a plurality of recesses therein arranged in a straight line, said recesses extending through the circular portion of said second body and into the prisrnoidal portion thereof, a contact element disposed in each of said recesses, and means electrically connecting said contact elements separately to the pins of said base.

3. An adapter for use with a fiat-bulb electron discharge tube, including, in combination, a pintype base havingv a plurality of pins arranged in a circle, an upstanding metallic shell at the periphery of said base, said shell having an inwardly-extending lip at its upper end, a diskshaped body of insulating material disposed within said shell, said body engaging the lower surface of said lip, a second body of insulating materialdisposed exteriorly of said shell, said second body consisting of a clrcularbase portion which engages the upper surface of said lip and an upstanding prismoidal portion, means for clamp ng said two bodies together on opposite sides of said lip, said second body having a plurality of recesses therein arranged in a straight .line, said recesses extending through the circular REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 995,970 Kemp June 20, 1911 1,707,252 Chubb Apr. 2, 1929 1,825,534 Mavrogenis Sept. 29, 1931 1,996,820 McCullough Apr. 9, 1935 2,186,184 'Iubbs Jan. 9, 1940 FOREIGN PATENTS Number Country Date 552,720 Great Britain Apr. 21, 1943 

